Excerpt from YouTube video description:
Cassava flour is made by peeling cassava foot, crushing or grating, dewatering under pressure (to reduce moisture content), dehydrating, milling & sifting. Is it a whole food? The dewatering step removes some nutrition.
A nice video showcasing all the steps in commercial cassava flour production.
The homemade process is similar to industrial process.
Sabudana granules (sago pearls | tapioca pearls) look like grains but they are actually a starch extract derived from cassava root. Check out these articles for details: Starch Extracts are not Whole Foods and Is Sabudana A Whole Grain?